Emily Adlam is a professor in the Schmid College of Science and Technology at Chapman University in Irvine, California.

In her 2021 book Foundations of Physics, Adlam has an extensive discussion of nonlocality.

It is a basic fact of our experience that our actions affect only those objects which are spatially co-located with us at the time of the action, and that we can influence more distant objects only by means of some mediating physical process - so. for example. we cannot communicate ideas instantaneously to people on the other side of the world, and are instead forced to take recourse to some mediating physical process such as putting a letter in the post. Further examination of the macroscopic world seems to bear out the conjecture that this constraint applies quite generally across the classical world, and therefore in classical physics it was more or less taken for granted that there could be no action at a distance.

But in the world of quantum mechanics. it seems this simple observation might no longer hold. if we prepare the parts of a composite system independently and then combine them...

Foundations of Physics, p.13

the result of such a procedure will be an entangled state. It might be tempting to suppose that entanglement is no more than a quirk of our choice of mathematical representation, but in 1964 John Bell showed that its existence has profound physical consequences.

To do so, BelI studied 'local hidden variable models' - that is, models in which all correlations between measurements on different systems can be traced back to correlations between hidden variables of the systems that were established during a local interaction at some point in their common past.

But there exist entangled quantum systems that violate this inequality, and therefore quantum systems cannot be fully explained by any local hidden variable model...

Foundations of Physics, p.14

To appreciate the significance of this result. it is important to distinguish quantum correlations from more familiar sorts of distant correlations. In his essay 'Bertlmann's Socks and the Nature of Reality,' Bell explained this by analogy to socks. Suppose I take a pair of socks from a drawer, separate them without looking at them, and then send one sock to Japan and another to Brazil. My colleagues in Japan and Brazil open their packages at the same time and immediately report their results to me: lo and behold, both socks are red! Of course, there is nothing mysterious about this distant, instantaneous correlation - it occurs because the sock were paired up before being separated, i.e. it can be accounted for in terms of local interactions in the past. But Bell's theorem shows that there exist correlations in quantum mechanics which cannot be explained in this way- no matter how much information is shared between the two quantum systems in the Bell experiment at the time when they are together, it is not possible to achieve the kind of coordinated measurement results exhibited by quantum mechanics using only that shared information. The mathematics seems to be telling us that the choice of measurement on one particle must instantaneously influence the state of the other particle, even if the measurements are made almost simultaneously at very distant locations.

Foundations of Physics, p.15

Information philosophy has explored the idea that those "local interactions in their common past" might be a "common cause" of the perfect correlations in the future measurements, based on the fundamental principle of conservation of momentum true in both classical physics and quantum physics.

It is well known that the final spin directions observed by Alice and Bob cannot have been created in the original entanglement, because Alice and Bob can choose to measure at an arbitrary angle and still get perfect correlations. See our web page on a common cause.

In her 2025 book Saving Science from Quantum Mechanics, Adlam suggests that a "useful way to understand the measurement problem is to see it as a problem of epistemology" and that she "will use the term 'measurement' quite generally to refer to any observation or interaction which can be regarded as yielding some kind of empirical knowledge." (p.11).

This is of course our "fundamental question in information philosophy, how does new information (or knowledge) enter the universe, since it began in a state of thermal equilibrium (maximum entropy and minimal information) since it began some 13.7 million years ago?

In the information physics solution to the problem of measurement, the timing and location of the "cut" or "Schnitt" of Heisenberg and von Neumann are identified with the interaction between quantum system and classical apparatus that collapses the wave function and leaves the apparatus in an irreversible stable state providing a record of information "observable" at that moment or any time later.

Von Neumann asked where exactly in the observer's mind or consciousness the "Schnitt" occurs. John Bell called this problem the "shifty split." Here is Bell's drawing. with our indication where the "Schnitt" belongs.

This is Adlam's "observation or interaction which can be regarded as yielding some kind of empirical knowledge."

It's not the observer's brain, mind, or consciousness that's needed to "collapse" a wave function. It's the irreversible interaction of the quantum system with another system. The interaction must be one that changes the information (or knowledge) about the system, so this is indeed Adlam's "empirical knowledge." And that means a local entropy decrease (a negentropy or information increase) and an overall entropy increase to make the information stable enough to be observed then or much later by an experimenter.

This two-stage irreversible temporal process randomly decreases the physical entropy locally (an increase in information), requiring a compensating increase in global entropy (and decrease in information elsewhere) to satisfy the second law of thermodynamics.

This is the deep relationship between immaterial information and material entropy that John Wheeler calls "It from Bit."

Adlam describes the measurement problem in great detail in her 2025 book Saving Science from Quantum Mechanics...

Evidently there is some kind of problem in the vicinity of measurement in quantum mechanics, but it turns out to be quite non-trivial to say exactly what the problem is and what it would take to solve it. The literature contains many different descriptions of the measurement problem - indeed, nearly everyone who works in this area seem to have a lightly different conception of what the problem is! - and naturally these different conceptions of the problem lead to different ideas about what a viable solution looks like.

In this book, I will suggest that one useful way to understand the measurement problem is to see it as a problem of epistemology. This presentation of the problem is a little different from some popular accounts, but I hope to make a care that this epistemic construal of the problem does indeed highlight a serious gap in our understanding of quantum mechanics, and moreover that conceptualising the problem in this way ultimately improves the prospects that it can actually be solved.

Before presenting this epistemic account of the measurement problem, let us start with a simpler question: what is a measurement? In this chapter l will offer a somewhat schematic answer to this question; later, in chapter 4, I will take a more detailed look at what recent work in epistemology has to say about the matter, fleshing out the details of the account I sketch below.

First note that my concern in this discussion is not to demarcate measurements from more general kinds of observations. The term 'measurement' is most commonly associated with scientific experiments performed specially designed laboratories but in a sense every time we open our eyes and look at the world around us or perceive it In some other way, we can be regarded as carrying out a rudimentary 'measurement' - indeed, science presumably has its origins in attempts to systematise the results of these simple kins of measurement. So in this book l will use the term 'measurement' quite generally to refer to any observation or interaction which can be regarded as yielding some kind of empirical knowledge, for example, measurement may include things like looking at the sky, reading a book, conversing with another person, or even merely consulting one's memories. Part of the reason for using the term in this way is that, as we will see in chapter 3, certain interpretations of quantum mechanics do actually suggest that all of these kinds of interactions involve the same kind of process as a more conventional 'quantum measurement,' so it is sensible to treat measurement in the most general possible sense here.

Thus construed, 'measurement' is "quite a special kind of category. On the one hand, it is an ontological category: a measurement is a physical process and so, at least in the context of physicalism or any other flavour of scientific realism, it is natural to think we should be able to describe what goes on during a measurement in purely physical terms. But measurement is also an epistemic category: it is nothing more or less than the ultimate contact point between our experience and physical reality. As van Fraassen (2008, p.143) put it, 'Measurement is an operator by whose means we gather information: but this is of course done by way of a physical interaction between apparatus and object, to play the information-providing role; and thus measurement has both 'physical and intentional aspects.'

Saving Science from Quantum Mechanics, pp.11-12

The measurement problem in quantum mechanics is the puzzle of how a smooth, multiple-possibility wave function collapses into a single, definite reality when someone looks at or measures it.

Quantum physicists from Werner Heisenberg and John Von Neumann to John Bell speculated that somewhere in the mind of the observer there is a "cut" or "Schnitt" that is the cause of the collapse. The solution is to see how new observable information is created by a measurement.

The mind of the observer has nothing to do with measurement. Today's measurement devices are often controlled by computers! The fundamental measurement event is the creation of new information, as little as a single bit of particle spin down or spin up, recorded in the measurement apparatus, and later available for any observer to see/measure.

In the cosmic creation process one new bit of information (negentropy) requires at least one bit of positive entropy to be radiated away to satisfy the second law of thermodynamics.

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